The thick colonic wall permits the creation of an antirefluxing ureterocolonic anastomosis, which reduces the incidence of pyelonephritis and limits the deterioration of renal function. Since 1977 a simple procedure for ureterocolonic anastomosis performed entirely outside of the colon was used in 63 patients. Obstructive complications were encountered in 6.4 per cent, while ureterocolonic reflux occurred in 5.6 per cent of the renoureteral units. Acute pyelonephritis developed in 7 patients.